The present invention concerns a plasticized-sulfur composition and concentrates useful in its preparation. In particular, the fully formulated composition comprises sulfur, an aromatic polymeric polysulfide sulfur plasticizer, a mica filler and a triarylphosphate. The composition is particularly useful as a coating material because of its surprising resistance to crazing under freeze-thaw cyclic weather conditions.
Plasticized-sulfur compositions are well known in the coating art. Various references disclose and compare the properties of these compositions. For instance, U.S. Pat. No. 3,823,019 describes plasticized-sulfur compositions comprising sulfur, dicyclopentadiene, glass fiber and talc. U.S. Pat. No. 3,290,266 describes plasticized-sulfur compositions comprising sulfur and a polymeric plasticizer. U.S. Pat. No. 4,026,719 describes various plasticized-sulfur compositions. In particular, this patent discloses the use of mica as a filler, which imparts exceptional strength to the compositions.
As the general state of the sulfur and plasticized-sulfur coating art developed, it became clear that these compositions were limited by their tendency to craze or crack when exposed to expansion or contraction stresses. Many coating applications, such as the coating of vessels intended to hold corrosive materials, require an essentially craze-free coating. Thus, in many cases the useful life of the coating is determined by its craze resistance.